Hey guys.. I got a few questions about converting my US41 to electronic ignition.. hope you can help

Ebay has this Rcexl ignition system for $75 .. that seems like a great deal to me.. but I'm a bit nervous about a few aspects of the conversion

The listing states " You provide your favorite switch and 4.8 battery and a hub for the special magnet that is included."

Is there a place to purchase a hub that will work with my engine? and what "switch" would you recommend I use?

also... since the spring starter will be deleted...would there be an advantage to removing the aluminum motor mount and replacing it with standoffs? I'm trying to lose as much weight as possible.. I'll post a pick of what all comes with this ignition.. any help would be greatly appriciated!